Two earthquakes rocked southwest Haiti on Monday, killing two people and damaging homes. The quake comes just 5 months after a temblor killed over 2,000 people. 

As rescuers search for survivors in the Caribbean nation, here’s a look at why Haiti has had so many devastating earthquakes over the centuries and why they are often so devastating.

WHAT MAKES HAITI PRONE TO EARTHQUAKES?

The Earth’s crust is made up of tectonic plates that move. And Haiti sits near the intersection of two of them — the North American plate and the Caribbean plate.

Multiple fault lines between those plates cut through or near the island of Hispaniola, which Haiti shares with the Dominican Republic. What’s worse, not all of those fault lines behave the same way.

“Hispaniola sits in a place where plates transition from smashing together to sliding past one another,” said Rich Briggs, a research geologist at the U.S. Geological Survey’s Geologic Hazards Science Center.

“It’s like a rock stuck in the track of a sliding glass door,” he said. “It just does not want to move smoothly because it’s got so many different forces on it.”

Also Read: Haiti earthquake has impacted over 1.2 million people: UNICEF

WHY CAN EARTHQUAKES IN HAITI BE SO DEVASTATING?

It’s a combination of factors that include a seismically active area, a high population density of 11 million people and buildings that are often designed to withstand hurricanes — not earthquakes.

Typical concrete and cinder block buildings can survive strong winds but are vulnerable to damage or collapse when the ground shakes. Poor building practices can also play a role.

Also read: In quake-hit Haiti, rescuers race to look for survivors

A quake in 2010 hit closer to densely populated Port-au-Prince and caused widespread destruction. Haiti’s government put the death toll at more than 300,000, while a report commissioned by the U.S. government placed it between 46,000 and 85,000.

“I think it’s important to recognize that there’s no such thing as a natural disaster,” said Wendy Bohon, a geologist with Incorporated Research Institutions for Seismology. “What you have is a natural hazard that overlaps with a vulnerable system.”

Also Read: In pics| Damage caused by 7.2 magnitude earthquake in Haiti

WHAT DOES THE FUTURE HOLD?

Geologists say they cannot predict the next earthquake.

“But we do know that earthquakes like this can cause similar-sized earthquakes on the next portion of the fault,” said Hayes of USGS. “And it’s quite a significant hazard in places that don’t have the construction practices to withstand the shaking.”

Construction of more earthquake-resistant buildings remains a challenge in Haiti, which is the poorest nation in the Western Hemisphere.

And while there have been some success stories of Haitians building more earthquake-resistant structures, the country has lacked a centralized effort to do so, said Mark Schuller, a professor of anthropology and nonprofit and NGO studies at Northern Illinois University.

Haiti’s government has become increasingly weak, while non-governmental organizations focus on their own compartmentalized projects.

“There is technical knowledge in Haiti. There are trained architects. There are city planners. That’s not the problem,” Schuller said. “The problem is a lack of funding for coordination, and lack of political will from donors (to organizations providing aid).”